The invention concerns a paper-feeding apparatus for a printer of the type where each time after one line is printed the paper is advanced automatically by the space of one line.
Such a printer typically comprises a main shaft which is turned by a drive motor for the printing operation and which carries a paper-transport cylinder freely rotatable and axially fixed. A pressure roller presses the paper elastically against the perimeter of the transport cylinder. A coupling wedge is provided which is axially movable and which rotates together with the main shaft. The wedge can be forced, counter to the elastic bias of a restoring spring, from an unencumbered position into recesses on the paper transport cylinder by a cam control to rotate the paper transport cylinder.
In the case of printers with paper-feeding devices of this type it becomes necessary, whenever a new paper roll is inserted or the printed portion of the paper is torn off, to advance the paper in the blank state (i.e., without printing) for several spaces. This operation in many cases is carried out by a handwheel which is turned for the purpose of advancing the paper, the handwheel being located at the side and coupled to the paper-transport cylinder. Alternatively, the printer must go through several printing cycles without positioning of the type in order to advance the paper by the necessary number of lines and thus utilizing the regular step-by-step feeding mechanism. The first solution requires special efforts by the operator while the second possibility takes a relatively long time to accomplish.
It is, therefore, the object of the invention, to utilize the available motor drive of the printer for a rapid blank feed of the paper as desired, and to accomplish this operation mainly by the use of components which are already provided for the step-by-step advance, in other words, without significantly increasing the number of parts of the printer.